I own a private gaming computer on which I'm using two X25-M 80 GB SSDs. The SSDs are obviously connected to the Intel SATA ports.

The mainboard is an "ASUS Rampage II Extreme" (Intel X58 chipset), but this might affect more mainboards (ASUS) with the same kind of hardware (JMicron controllers).

It was impossible for me to update the firmware on this mb, no matter which setting I've used in the BIOS (compatible, AHCI,...). Since some on this forum already discovered, it helps to disable any additional IDE/SATA controllers in BIOS, which im my case was a JMicron, used primarily for the eSATA port. But even then it didn't work in compatible (legacy) mode for me. I had to choose exactly this combination, all others failed:

Got the same message, though I could see my 80 GB X25-M just fine. You mentioned the one magic word for me: eSATA. It seems that there is another controller in my HP DV7-3060 that controls the eSATA port, and possibly the SD card slot. I have no choice in my BIOS setup that allows me to disable it, but I did happen to have the magic combination to deal with it. A while back, I bought an extermal NavStar SATA drive dock that allows me to just drop in either a 3.5 or 2.5 inch drive. I have used it previously to transfer files. Not only does it have a USB port, it has an eSATA port. When I pulled my SSD drive out of the notebook and put it "naked" into the external drive, cconnected to my laptop's eSATA port, boot disc saw it just fine, and updated the firmware. So that is a pretty specific set of circumstances, but it did work, and may give other people some clues.

After I upgraded, CrystalDisk showed that I do now have TRIM, but honestly, the benchmark specs didn't budge a bit. I was able to create a partition in exactly the right place for alignment, and I'm running Win 7 64 bit, but my 4k read was only 14 mB/s, and write was 24 MB/s; overall though, my read was 250 MB/s and write was 82 MB/s. Sure beats the old spinner, evan at 7200 RPM